All manner and variety of absorbent articles configured for the absorption of bodily fluids are, of course, well known. Current types of absorbent articles include sanitary napkins, pantiliners, disposable diapers, and incontinent articles.
One material which has been widely utilized as a topsheet material in absorbent articles is disclosed in commonly assigned U.S. Pat. No. 4,342,314 issued to Radel, et al. on Aug. 3, 1982 and hereby incorporated herein by reference. Radel, et al. discloses an absorbent bandage with a wearer-contacting topsheet comprising a resilient, macroscopically expanded, three-dimensional plastic web exhibiting a combination of fiber-like and plastic properties. In a preferred embodiment, the macroscopically expanded, three-dimensional, plastic web topsheet disclosed in Radel, et al. exhibits a fine scale three-dimensional microstructure comprising a regulated continuum of capillary networks originating in and extending from one surface of the web and terminating in the form of apertures in the opposite surface thereof to promote rapid fluid transport. The web's fiber-like appearance is comprised of a continuum of fiber-like elements, the opposed ends of each of the fiber-like elements are interconnected to at least one other of the fiber-like elements.
A typical capillary network in the Radel, et al. structure comprises an uppermost capillary opening or aperture formed by a multiplicity of fiber-like elements interconnected to one another in the uppermost plane of the web. Each of the fiber-like elements exhibits a substantially uniform U-shaped cross-section along its length. The cross-section of the fiber-like element comprises a base portion located in the wearer-contacting plane and a sidewall portion joined to each edge of the base portion, the sidewall portions extend generally in the direction of the absorbent pad-contacting surface of the web. The sidewall portions which intersect one another are joined to one another intermediate the wearing contacting surface and the absorbent pad contacting surface of the web, thereby forming a capillary network interconnecting the opposed surfaces of the web.
A topsheet of the type generally disclosed by Radel, et al. is highly effective in promoting rapid fluid transfer from the first, wearer-contacting surface to the second, absorbent pad-contacting surface of the topsheet. Accordingly, topsheets of this type have enjoyed widespread commercial success on catamenial pads due to their clean and dry appearance in use when contrasted to conventional nonwoven fibrous topsheets or two-dimensional films. While an absorbent article having a topsheet of the type disclosed in Radel, et al. is highly effective in promoting rapid transfer of bodily fluids from the first, wearer-contacting surface to the second, absorbent pad-contacting surface, the degree of masking of bodily fluids, e.g., menses, retained within the absorbent core is dependent upon the size of the capillary networks. As the size of the capillary networks decrease the amount of masking provided by the topsheet increases. However, if the capillary networks are too small bodily fluids are not able to pass through the topsheet into the absorbent core thereby exposing the skin to moisture. Furthermore, the three-dimensional structure of the film tends to limit its ability to expand and contract in sheet-wise dimension (extensibility) in response to in-use forces, in turn limiting the ability of the absorbent article to accommodate various postures and activities of the wearer. Due to their three-dimensional structure and the molecular orientation imparted to the formed film during the formation process, it has been difficult to impart extensibility and additional softness to such films via post-formation mechanical processes without causing destruction and/or damage to the three-dimensional capillary structure and hence degradation in fluid handling performance.
Conventional nonwoven topsheets have been found to provide desirable visual and tactile properties from the wearer's perspective, as well as good flexibility and softness properties. However, the fluid-handling performance of conventional nonwoven topsheets has been found to be less than optimal, particularly with comparatively more viscous bodily fluids, contributing to a "wet" tactile impression after exposure to bodily fluids. In addition, while conventional nonwoven topsheets provide a masking effect with regard to the underlying absorbent article components, residual fluid remaining within the nonwoven material itself after use creates a less-than-desirable visual impression. Unlike formed film materials, nonwovens utilized for topsheet applications have been comparatively easier to subject to post-formation mechanical processes to impart extensibility and additional softness while maintaining their original properties.
Accordingly, it would be desirable to provide a fluid pervious web suitable for use as a topsheet in an absorbent article which provides the fluid handling capabilities of a formed film material and the softness of a nonwoven material.
It would also be desirable to provide a topsheet material having desirable visual and tactile properties, including a soft tactile impression.
It would be further desirable to provide such a topsheet material which provides sufficient stretchability and extensibility to accommodate a wide range of in-use conditions and to enable the absorbent article to better conform to the wearer's body.